> Unfortunately not but it did get me on the right track. The problem is > caused by the e100_watchdog function. As far as I can tell e100_watchdog > is called from a timer queue and therefore runs with the priority of > that thread. And while I set higher priorities for softirq-net-rx and > the application I missed the thread for the hardware interrupt of the > network interface. So whenever a packet arived while e100_watchdog was > running it got delayed. The periodic pattern is a result of this and > speed difference of sender and receiver clocks. > The jitter is now <50us but still with some periodic patterns. So I'll > need to investigate further. > There was some discussion going on this issue on netdev .... The below link might help you. http://www.nabble.com/Re%3A-My-vote-against-eepro*-removal-t954330.html#a2532617 -- Thanks Giri - To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html